System requirements:

• Intel 80486DX2/66 MHz or a compatible CPU with a math coprocessor (Pentium processor recommended)
• 16 MB of RAM (24 MB recommended, it's possible to run on 8 MB machines with /nm option used during the installation process)
• At least 500 MB of space available on HDD. The amount of space required depends on the installation method and the components selected, but virtual memory and system utilities as well as drivers should be taken into consideration.

• Upgrading from Windows 95 (FAT16) or 3.1 (FAT): 140–400 MB (typically 205 MB).
• New installation (FAT32): 140–255 MB (typically 175 MB).

• VGA or higher resolution monitor (640x480)
• CD-ROM or DVD-ROM drive (floppy install is possible but slow)
• Microsoft Mouse or compatible pointing device (optional).

Users can bypass hardware requirement checks with the undocumented /NM setup switch. This allows installation on computers with processors as old as the 80386.

Windows 98 VCACHE is not designed to handle more than 1.0 GB of RAM without little changes.

Both Windows 98 and Windows 98 SE have problems running on hard drives bigger than 32 Gigabytes (GB) and certain Phoenix BIOS settings. A software update fixed this shortcoming. In addition, Windows until XP without Service Pack is unable to handle hard drives that are over 137 GB in size with the default drivers, because of missing 48-bit LBA support – disc data corruption is likely. Third party patches are available to fix this shortcoming in Windows 9x.

-Wikipedia-